This invention relates to fluorescent lamp crushing apparatus, and more particularly to an improved method and associated apparatus for simultaneously separating and delivering to separate containers components of crushed fluorescent lamps and the like, such as end caps, fluorescent powder and glass.
Fluorescent lamps in tubular form are the dominant indoor light source for offices, shops, laboratories and industrial plants. While they are produced and employed in linear, circular and U-shaped configurations, the mainstay of tubular fluorescent lamps appear to be four foot and eight foot long linear fluorescent tubes, which have diameters of 1.5 inches (38 m.m.). Lamps of the type described have a lifetime Of about 8,000 to 10,000 operating hours. Typically they last from one to three years depending upon the use cycle. In some shops and offices replacement of failed lamps is performed on a demand basisxe2x80x94i.e., when the ends of the lamps turn black and reduced output is noted. In many other situations, and particularly in large office complexes and manufacturing plants, fluorescent lamp replacement for a whole floor or area is performed on a scheduled basis, when the affected lamps are known to have been in service for a specific period of time. In each situation, a rather significant spatial volume of spent fluorescent lamps quickly accumulates and requires disposal.
One solution for disposing large volumes of such lamps is to employ machines which safely crush the lamps into near powder form. Several such lamp crushers are disclosed, for example, in U.S. Pat. Nos. 4,655,404, 5,205,497 and 5,575,429, each of which patents is owned by the assignee of the present application. As disclosed in those patents, the discharge ends of the respective crusher machines usually communicate with 55 gallon drums which receive the crushed components, while mercury vapors and the like that are discharged upon the crushing of the lamps are being accumulated in associated filter mechanisms. Lamps of the type described contain mercury, portions of which when the lamps are crushed, are retained by the above-noted filter mechanisms, but residual mercury in the crushed lamps can constitute a health hazard when present in significant quantities. For that reason it is customary for the above-noted drums containing the crushed lamps carefully to be sealed for shipment and storage, thereby promoting sound environmental handling of the lamp crushing.
Disposal of crushed fluorescent lamps in the manner noted above still represents a long term environmental hazard, since the drums containing lamp waste eventually will rust through, resulting in leakage of their contents to the environment. While this consequent leakage may take some time to occur, recycling of the ingredients of crushed fluorescent lamps is viewed by many environment jurisdictions to be the better and eventually only practical solution. In accordance with the invention disclosed herein, the first step in such recycling process is the mechanical separation of the main ingredients of the lampsxe2x80x94namely, the glass, end caps and the fluorescent powder (halo-phosphate) components. In addition, each such fluorescent tube normally contains a small quantity of metallic mercury, e.g. in the vicinity of 25 to 50 milligrams, which attaches to most components of the lamps, but mainly spreads throughout the fluorescent powder. While U.S. Pat. No. 5,092,527 and 5,492,278 have disclosed apparatus for crushing fluorescent lamps and separating the components thereof, such prior art equipment has proved to be unsatisfactory in connection not only with the efficiency of the crushing of layers and the separation of components, but also in connection with the rate at which lamps can be crushed and separated.
Accordingly, it is an object of this invention to provide a novel method of separating the constituant components of the crushed fluorescent tubes into end caps, fluorescent powder and glass, near or adjacent to their points of origin in the lamp crushing cycle, thereby to maximize the ability to compact and thus ease subsequent handling of the components. In this way each of the various components may be treated or otherwise handled or disposed of by machinery which forms no part of this invention, and which may be capable of recovering the mercury and purifying the residues so that the latter may serve as the raw materials for new fluorescent lamps.
Still another object of this invention is to provide improved lamp crushing apparatus having associated therewith a novel separating mechanism which separates and delivers various components of the crushed lamps to separate containers for use as raw materials in the production of new lamps.
Other objects of the invention will be apparent hereinafter from the recital of the appended claims when read in conjunction with the accompanying drawings.
To convey the components of crushed fluorescent lamps from lamp crusher housing to a cyclonic hopper, a duct is connected at one end to an outlet of the crusher housing and at its opposite end the hopper adjacent its upper end. A large blower has an outlet connected to the duct to blow air through the duct in the direction away from the crusher housing and toward the hopper thereby generating a vacuum at the crusher housing outlet and pneumatically conveying the lamp components tangentially into the hopper, where the heavier glass particles and caps are allowed to drop by gravity into a separator housing where they are separated from each other and discharged into different storage containers. The upper end Of the hopper is connected to the inlet of the fan so that lighter glass particles and dust are recirculated back to the crusher housing. Another vacuum source draws dust and vapors pneumatically from adjacent the bottom of the hopper and tangentially into a cyclone filter housing where particulate matter is allowed to drop into a dust collector, and draws lighter dust and vapors from the upper end of the cyclone filter housing to a dust and mercury filter. In addition to rotating crusher blades the crusher housing contains a paddle element which rotates with the blades and mechanically sweeps lamp components towards the crusher housing outlet.